Showing papers in "Journal for Manufacturing Science and Production in 2006"

Desirability Function Approach for Solving Multi-Objective Optimization Problem in Submerged Arc Welding

Abstract: Like any other welding technique, Submerged Arc Welding (SAW) is also a multi-objective, multi-variable metal processing technology. In general, the acceptability of a weldment depends on various parameters in relation to bead geometry, bead quality, microstructure and mechanical-metallurgical characteristics of the weld, that can fulfill the required goal. The acceptable limits of these parameters are also influenced by the area of application as well as functional requirements of the prepared weld. Therefore, there exists a need to search for an optimal process condition that may achieve the desired purpose. In the present work, it is aimed to search for an optimal solution for the process parameters that would result in maximum depth of penetration, minimum height of reinforcement, minimum bead width, minimum dilution, minimum area of reinforcement and minimum area of penetration, within experimental domain. Data, collected from previous research for four factor-five level central composite design, have been utilized to determine individual desirability of the responses, which have been used further to calculate composite desirability associated with overall features of bead geometry and bead volume of the desired weldment. Desirability function optimization approach, followed by Response Surface Methodology (RSM), has been incorporated to evaluate the optimum parameter setting that would meet * Communicating Author the overall desirability of the weldment. Comparison of optimal parametric combination as determined by the previous researchers to that obtained by using desirability function approach and RSM has also been made. Good agreement has been found. This proves the application feasibility of desirability function approach coupled with RSM for solving multi-objective optimization problems in SA welding.

Interoperability between a Cooperative Design Modeler and a CAD System: Software Integration versus Data Exchange

Abstract: The data exchange between Computer-Aided Design (CAD) systems is a crucial issue in concurrent engineering and collaborative design. The paper presents research works and techniques dealing with the interoperability of a Cooperative Design Modeller (CoDeMo), aiming at the integration of product lifecycle knowledge, and a commercial CAD system (CATIA V5). Two kinds of approaches are implemented in the considered case of CAD interoperability for exchanging geometric data, respectively: one is based on a traditional static interface, in which STEP AP203 standard is used; the other is based on a dynamic interface, in which Application Programming Interfaces (API) of the targeted CAD system is adopted. Both approaches should enhance the communication, exchange and sharing of product data between CAD systems for improving concurrent engineering. A comparison between these two approaches is made to show their particular advantages and disadvantages. The development of a translator between the both CAD systems based on each approach has been carried out and evaluated on an assembly case.

Performance of Copper and Aluminum Electrodes During EDM of Stainless Steel and Carbide

Abstract: The present work gives a comparative analysis of the performance of copper and aluminum electrodes for machining stainless steel and carbide. It was found that MRR (material removal rate) increases with increase in current and voltage, but MRR is higher during machining of stainless steel than that of carbide. During machining carbide, electrode wear and corner wear were higher than those during machining stainless steel. Wear of copper electrodes was less than that of aluminum electrodes. Volumetric wear ratio, i.e., the ratio of the material removed from the work to the same removed from the electrode decreases with increase of current or voltage. This means that comparatively more material is removed from the electrode than that removed from the work. Investigations on work surface finish show that aluminum electrodes produce smoother surface than copper electrodes during machining of both stainless steel and carbide. The surface was found to be smoother on carbide than on stainless steel. Author

Sensitivity Analysis of Flux Cored Arc Cladding Parameters Using Response Surface Methodology

Abstract: Cladding is a process of depositing a thick layer of a metal surface to a carbon or low alloy steel base metal for the purpose of providing a corrosion resistant surface when that surface is to be exposed to a corrosive environment. In cladding process, most engineers often face the problem of selecting optimum combination of input process parameters for achieving the required clad bead geometry. Until recently trial and error methods were used to determine the optimum process parameters, which result in wastage of cost and time. This paper focuses on an experimental study on duplex stainless steel cladding of low carbon structural steel deposited by flux cored arc welding process. Experiments were conducted based on four-factor, fivelevel central composite rotatable design with full replications technique. Mathematical models relating flux cored arc welding process parameters to clad bead geometry were developed using multiple regression method. The precision of the results was tested by conducting conformity tests using the same experimental setup. Further, optimization was carried out using Quasi-Newton method. Developed mathematical models are helpful in predicting the clad ' Communicating author bead geometry and in setting process parameters at optimum values to achieve the desirable clad quality at a relatively low cost with a high degree of repeatability. Sensitivity analysis was carried out to analyze the effect of relaxing the limits of the constraint functions independently and collectively on the value of the objective function and other constraint functions. The results are presented in graphical forms.

Optimum Cutting Speed for Machining Stainless Steel with Coated Carbide Tools

Abstract: Among the cutting parameters, cutting speed is the riost prominent factor responsible for tool wear during machining. Increase in cutting speed causes a dramatic reduction in tool life while feed variation and depth of cut at high cutting speeds have small affect on tool life. Taylor's tool life equation and many research works demonstrated that tool life decreases with increase in cutting speed. In the present work it was shown that increase in cutting speed does not always decrease tool life. In the present work stainless steel SUS 304 was machined by coated carbide inserts type PI5 on a lathe machine both without coolant and using coolant. During the whole experimental works the feed rate and the depth of cut were kept constant at 1 mm/rev and 1 mm respectively. Cutting speed was varied within a range from 250 m/min to 360 m/min. It was found that in both the cases of dry machining and machining with coolant, initially tool life increases with increase in cutting speed, reached a maximum value and then decreased with further increase in cutting speed. This is due to the fact that at low cutting speed, the heat generated is low compared to that at high cutting speed. At a low cutting speed the temperature developed is not very high and the work piece is still hard. As a result, the tool rapidly becomes worn. But as the cutting speed is increased, more heat is generated and the work piece becomes softer while the tool still retains its hardness due to its high hot hardness temperature. As a result, tool life increases. But at a very high cutting speed the temperature developed is very high which exceeds the hot hardness temperature of the tool. This causes higher tool wear rate. Thus, for any particular machining setup there exists an optimum cutting speed for which tool life can be maximized. It was also found that while coolant is applied from the top of the tool, application of coolant is effective only at low cutting speeds and at a very high cutting speed application of coolant is absolutely ineffective. K e y w o r d s : Optimum tool wear, Cutting speed, Stainless steel, Coated carbide tool

Desirability Function Approach for Optimization of Bead Geometry in Submerged Arc Welding Using Factorial Design and Response Surface Methodology

Abstract: Response Surface Methodology (RSM) and desirability function (DF) approach have been applied to evaluate the optimal parametric combination in submerged arc welding on mild steel. Experiments have been conducted using three different levels of process parameters including welding current and flux basicity

Thermal Plasma Production of B4C Nanopowders

Abstract: Irregular shaped micro-sized B4C powders have been produced using conventional powder production techniques. Spherical nanoscale powders can remarkably improve the effective use of B4C powders as a coating material and also as a reinforcing phase in metal-matrix composites (MMC). Production of B4C nanopowders from B 2 0 3 powder and CH4 gas as reactants is carried out employing thermal plasma technology. The effect of experimental variables, viz. B 20 3 :CH 4 mole ratio, power input and B 2 0 3 feed rate on product recovery and product particle size, is studied. A stoichiometric B 2 0 3 :CH 4 mole ratio, high power input and slow B 2 0 3 feed rate are preferred parameters to produce powders with higher purity and smaller particle size. The product powders were characterized using SEM, XRD, and BET for composition, particle size and morphology. A maximum product recovery of 93.7% by volume is obtained for the experimental results against the cxpected recovery of 100% by mole theoretically. Some free carbon and in some experiments B 2 0 3 powders are also found in the B4C product powders which decrease the product recovery. Average spherical particle size of 80 nm was produced with a particle size distribution in the range of 10 nm 200 nm. The particles are highly spherical in nature. K e y w o r d s : Boron Carbide (B4C), Nanopowders, Plasma, BET, Quantitative XRD * Corresponding author email: rreddv@coe.eng.ua.edu

Process Parameter Optimization Using Response Surface Methodology for Turning

Abstract: The experimental investigations of the tool wear and surface roughness for turning of Grey cast iron at different cutting parameters are reported in this paper. This paper also outlines an approach to quantify specific relationships between cutting parameters and tool wear and surface roughness. The model is formulated using Response Surfaces methodology. There are three input parameters, i.e. speed, feed and depth of cut, and two output parameters, i.e. tool wear and surface roughness. Response surface plots are indicated by taking two input parameters along X-axis and Y-axis, keeping a third one as a constant and one output parameter along Z-axis. Then the interaction of these parameters is also shown as two-dimensional representation. Response surfaces were reported for each output parameter viz. Tool Wear and Surface roughness. The mathematical model is formulated. This model is capable of estimating the wear rate and surface roughness at different cutting conditions. The model performed quite satisfactory results with the actual and predicted tool wear values. Optimum cutting parameters can also be obtained using this model.

A Model for Cutting Tool Wear Estimation

Abstract: An experimental investigation on cutting tool wear and a model for tool wear estimation is reported in this paper. The changes in the values of cutting forces, vibrations and acoustic emissions with cutting tool wear are recoded and analyzed. On the basis of experimental results a model is developed for tool wear estimation in turning operations using Adaptive Neuro Fuzzy Inference system (ANFIS). Acoustic emission (Ring down count), vibrations (acceleration) and cutting forces along with time have been used to formulate model. This model is capable of estimating the wear rate of the cutting tool. The wear estimation results obtained by the model are compared with the practical results and are presented. The model performed quite satisfactory results with the actual and predicted tool wear values.

Reliability Modeling and Analysis of Composite Product System - A Systems Approach

Abstract: In the present scenario application of composite products has been extended enormously in Naval, Military, Civil aircraft structures, in addition to more exotic applications on unmanned aerial vehicles, Space launchers and Satellites. Selection of suitable composite products to the given application has become an important aspect in composite industry. The present paper describes a methodology for the reliability analysis of composite product system as well as optimum selection based on reliability. A detailed procedure for the reliability analysis of polymer matrix composite product system is suggested through a reliability function. The approach is based on graph theory and matrix algebra, and this takes into account complexities and interrelations of subsystems existing in polymer matrix composite product. Exhaustive and useful reliability analysis of a system is carried out based on reliability-based tests for the composite product system. Coefficients of similarity or dissimilarity, which compare two composite product systems based on reliability, are developed. Quantitative evaluation of the reliability of a system through the reliability index is proposed in this paper. This aids in the optimum selection of a composite product system at the initial stages of design. The methodology is flexible and general in nature and can be used by the designer and manufacturer on the basis of its selected subsystems and reliabilities related to them at the conceptual stage of design. The proposed methodology is illustrated through an example of a Resin Transfer Moulding (RTM) composite product system.

Mathematical Modeling for Study of Parametric Influence on Bead Height, Bead Width and Depth of Heat Affected Zone of Submerged Arc Bead-on-Plate Weldment

Abstract: Mathematical models have been developed to study the influence imposed by the process control parameters on bead geometry and HAZ of submerged arc weldment. Experiments have been performed with different levels of process parameters like welding voltage, current, wirefeed rate and traverse speed to obtain bead-on-plate weld on M.S. plates by submerged arc welding (SAW). Nonlinear mathematical models have been assumed to represent the complex relationship between process parameters and the response variables associated with features of bead geometry and HAZ of the weldment. Multiple linear regression method has been used to calculate the constant terms included in the models. The adequacy of the proposed models has also been tested statistically. Predictions as obtained by the models have been utilized to reflect direct as well as interactive effects of process parameters on bead height, bead width and depth of HAZ of the weldment. K e y w o r d s : SAW, HAZ, multiple linear regression

An Experimental Study on Effect of Drill Points and Drill Wear on Drilling of Glass Fiber Reinforced Plastic at High Spindle Speed

Abstract: High speed machining is now recognized as one of the key manufacturing technologies for higher productivity and throughput. It is well known that the most effective way of achieving good quality holes while drilling fibre reinforced plastics is by reducing the thrust and torque. So, drilling experiments were conducted with drill points, namely standard twist drill, Zhirov-point drill, and multifacet drill, using wide range of spindle speed, and feed rate to analyse thrust force, delamination and surface roughness. In drilling of composites, high spindle speed and low feed rate improve the machinability aspects within the range examined. The cutting force is less and the special geometry improves the quality of the hole further, especially Zhirov point drill. Multifacet drill is found better as far as the delamination value is concerned.

The Fabrication and Heat-treating of Cu-based Alloy for Shape Memory Plates

Abstract: This work is concerned with the development of a Cu-22.3mass%Zn-5.1mass%Al alloy that is potentially usable for shape memory devices. The influence of betatizing heat treatment parameters on the grain size of the alloy was evaluated. The optimal thermomechanical treatment for obtaining thin plates with final thickness below 1 mm was selected from the standpoint of least danger of crack occurrence, favorable microstructures and acceptable grain size. A good reliable shape memory effect in the alloy is observed for stepquenched specimens. The decrease in the phase transformation temperatures was observed during aging treatment from 200 to 400°C for times up to 30 hours. The apparent activation energy for the decrease in the transformation temperatures was determined as 63.9 ± 3 kJmol\" .The conditions for producing a high quality memory device were suggested. K e y W o r d s : Cu-Zn-Al shape memory alloy, thermoelastic martensitic transformation, shape memory recovery

Cylindrical Cup Drawing with Hydrodynamic Pressure Assisted Blank Holding

Abstract: An innovative forming technique involving hydrodynamic pressure assisted blank holding for deep drawing cylindrical cups is presented. This process facilitates full film lubrication in the blank-blank holder interfaces and numerous advantages were envisaged in this technique. Analytical relations pertaining to the pressure generation were derived and the resulted effects were predicted through finite element simulations. Deep drawing quality low carbon sheet metal of 0.7 mm thickness with transversely anisotropic elastic plastic property was used in the simulation.

Modeling of Centrifugal Casting of Aluminum Alloy Components

Abstract: A mathematical model for centrifugal casting process of aluminum alloy tubular components was developed. It was found that thermal energy transfer between aluminum alloy and mold plays an important role in the surface quality of cast pipe and the uniformity of the pipe thickness. The mold mass and the thermal capacity are also important to the quality of cast pipe. Calculations were performed based on properties of mold coating materials. Modeling calculation indicated that only the coating materials with very low thermal conductivity could result in long-enough time for solidification and uniform quality of cast pipe. The calculation results showed that thermal conductivity of coating materials should be in the range of 0.1-0.8 W/mK at the experimental conditions discussed herein. Based on the model calculation results, a novel casting mold was proposed, designed and fabricated. Experiments were carried out in both regular and novel molds. The experimental results using 356 aluminum alloy cast in novel mold showed that the quality of cast pipe was improved. The regular casting mold was made of steel with different coating material at inner surface. The novel mold was comprised of outer cylinder, inner cylinder and insulator in between the cylinders. Aluminum silicate felt was used as insulator. The model results also showed why pre-heating of mold and regular coating could not significantly improve the surface quality and uniform thickness of the cast pipe by traditional mold casting method. 3 Corresponding author email: rrcddyC«' cng.ua.edu K e y w o r d s : Centrifugal casting, Modeling, Mold coatings, Casting parameters, Al alloys,

Optimization of Roll Grinding of D2 Steel With Multiple Performance Characteristics Using Taguchi Method with Fuzzy Logics

Abstract: The application of the Taguchi method with fuzzy logic for optimizing the steel work roll grinding process in the steel industry has been reported in this paper. A multi-response performance index is used to solve the roll grinding process with multi performance characteristics. A fuzzy reasoning of the multiple performance characteristics has been performed by the fuzzy logic unit. The grinding parameters such as wheel speed, work speed, traverse speed, in feed, dressing lead and depth are optimized with considerations of the multiple performance characteristics such as surface roughness and power required at spindle. As a result, the performance characteristics such as surface roughness and power required can be improved through this approach. Experimental results are presented to demonstrate the effectiveness of this approach. As a result, the optimization methodology developed in this study is used to improve multiple performance characteristics of work roll grinding operation.

Performance of Fully Active Suspension System Using PID Controller

Abstract: Suspension system design plays an important role in improving passenger ride comfort. Traditionally automotive suspension designs have been a compromise between the three conflicting criteria of passenger comfort, suspension travel and road holding ability. The present work aims at developing an active suspension for the quarter car model of a passenger car to improve its performance by using a proportional integral derivative (PID) controller. The controller design deals with the selection of proportional, derivative gain and integral gain parameters (Kp, Kd and Ki). To verify the performance of active suspension system we simulated the resulting closed loop system for a bumpy and step road profile using MATLAB 7.1 and compared the active suspension with passive suspension. The results show that the active suspension system has reduced the peak overshoot of sprung mass displacement, sprung mass acceleration, suspension travel and tire deflection compared to passive suspension system.

Phase Transformation and Residual Stress Analysis in Grinding of Steel Materials - A Detailed Experimental Investigation

Abstract: Grinding processes introduce residual stresses due to non-uniform changes induced by the process within the body. These stresses influence the mechanical properties like fatigue strength, depending on their nature, magnitude and distribution across the body. There is no material (or) situation free of these stresses. Hence, the great interest today is the recognition and measurement of these residual stresses along with phase transformation study. If the phase transformation is martensite to ferrite/pearlite, the volume decreases hindered by the bulk material produces tensile residual stresses. If the phase transformation is ferrite/pearlite to martensite, the volume increases hindered by the bulk material produces compressive residual stresses. With this in mind the effects of temperature on the phase transformation and residual stress of various percentage carbon steels subjected to cylindrical grinding process are studied and discussed in this paper.